Interactive · 2 questions
Introduction to Stars & Stellar Structure
As a child, you may have sung the song 'Twinkle, Twinkle' or wished upon a shooting star.
But what are stars anyway?
That's right: stars are enormous balls of gas held together by gravity and powered by nuclear fusion. Our sun is a star, as well as most objects you can see in the night sky. Some stars 'live' alone, while others 'live' in binary systems or enormous clusters. But all stars are big enough and have high enough pressures in their cores to fuse atomic nuclei and release enormous amounts of energy.
The size of stars is hard to comprehend. How large is the sun, a medium sized star, compared to the earth?
Of course, some stars are larger than others.
The smallest stars are only a few times wider than Jupiter, but tens of times more massive.
Some giant stars are thousands or millions of times more massive than the sun! (The small yellow dot on the far left is the sun.)